An experiment was conducted to measure the response of goat kids to supplementary feeding of their dams with protected fat (calcium soap of fatty acids). At birth, 22 single male goat kids were distributed in two groups according to the dams’ diet supplemented with 0 (dam control diet, DCD) or 100 (dam protected fat, DPF) g/day of protected fat through lactation. Higher energy intake of dams given protected fat caused higher fat content of their milk (P < 0·01) and the fatty acid profile was affected with a reduction of lauric acid (P < 0.01) and myristic acid (P < 0.01) and an increase in palmitic acid (P < 0.01). Goat kids were suckled by their dams from birth until the end of the experiment and had access to a creep food from 7 days of age. Kids were slaughtered at 45 days of age. There was no significant response (P > 0Ό5) in terms of kid mean live-weight gain, being 172 g (DPF) compared with 148 g (DCD). Fatty acid composition of the perirenal fat showed some differences between groups. Fat composition of group DPF was significantly higher in palmitoleic, oleic and linoleic acid content. In addition, myristic, palmitic and stearic acid had lower values. Fat of goat kids of the DPF group was more unsaturated (43·3 g per 100 g) than fat from animals of the DCD group (32·5 g per 100 g). In the DPF group, oleic acid comprised most of the unsaturated fatty acid due to its important increase compared with fat composition of the DCD group. In conclusion, fatty acid composition of fat depot in goat kids can he modified by feeding of the dams through lactation, which could be useful for possible changes according to market demand.

Twenty-eight Holstein/Friesian dairy cows were divided into four groups of seven. From weeks 4 to 15 of lactation they were given a basal diet consisting of 8 kg hay, 2 kg sugar-beet feed and 2 kg grass nuts, together with a concentrate allowance of 8 kg/day. Concentrates for group A were based on cereals and soya (control). Concentrate B contained 60 g protected fat supplement per kg; concentrate C contained 100 g lactose per kg; concentrate D contained 60 g fat supplement and 100 g lactose per kg. Milk yields were 24·6, 27·7, 25·6 and 26·5 kg/day and milk protein concentrations were 32·3, 30·7, 32·7 and 31·9 g/kg for groups A, B, C and D respectively. The effect of fat supplementation on milk yield and protein concentration was significant (P < 0·05) but the effect of lactose was not significant. Milk fat concentration was not significantly affected by treatment. It is concluded that lactose can partially alleviate the depression in milk protein concentration often observed when cows are given protected fat.

In two experiments, the effects of protected fat and fibre were studied in compound supplements for grazing dairy cows. The protected fat used consisted of calcium salts of long-chain fatty acids. In experiment 1, 17 cows (group S) were given 4 kg/day of a starchy compound and 17 (group F) 4 kg/day of a high-fibre compound containing protected fat for the first 4 weeks after turn-out to grass. No significant difference was found between groups in milk yield, but cows in group F produced milk with a higher fat content (42·6 g/kg) than did those in group S (37·1 g/kg; P < 0·01) and had higher yields of fat (0·88 v. 0·79 kg/day; (P < 0·05). In experiment 2, four groups of five cows were given 4 kg/day of starchy (S) or fibrous (F) compounds, with (P) or without (C) protected fat for the first 4 weeks after turn-out. After 4 weeks, treatments (starchy or fibrous, added fat or none) were reversed for a further period of 4 weeks. There was no significant effect on milk yield, milk protein yield, live-weight change or change in condition score, although cows on treatment SC tended to produce less milk and have greater gains in live weight and condition. For groups SC, FC, SP and FP respectively, milk fat yields (kg/day) were 0·86, 0·98, 0·99 and 1·06 (s.e.d. 0·06); milk protein contents (g/kg) were 34·4, 34·8, 34·2 and 33·0 (s.e.d. 0·68) and calculated milk energy outputs (MJ/day) were 67/2, 74·3, 74·4 and 76·6 (s.e.d. 3·04). It is concluded that substituting fibrous compounds for starchy compounds tends to increase milk fat content and yield; adding calcium salts of fatty acids to either type of compound significantly increases milk fat content and yield but tends to decrease milk protein content.